Under the deal announced Monday, the Galaxy also received the rights to midfielder Baggio Husidic. The Rapids received an international roster slot through the end of the 2014 MLS season and Los Angeles' second-round pick in the 2014 MLS SuperDraft.

Mastroeni will be eligible to make his Galaxy debut when Los Angeles hosts the Portland Timbers on Wednesday night.

The 36-year-old Mastroeni has spent the last 12-plus seasons with the Rapids, leading the club to its first MLS Cup championship in 2010.

A former member of the U.S. men's team, Mastroeni played in the 2002 and 2006 World Cup under current Galaxy coach Bruce Arena.